Learners combine Boyle's Law and Charles's Law to solve for the pressure, volume, and temperature of a gas sample under two sets of conditions.

Learners read the definition of atomic weight and obtain the weights of elements by viewing the Periodic Table and charts that list atomic weights by name or symbol.

Boyle's Law states that gas volume varies inversely with the pressure at constant temperature and is described by the equation PV = constant. An example of a sample of gas at two conditions of P and V is used to illustrate the law.

In this animated and interactive object, learners examine the inverse proportionality of wavelength and frequency and their relationship to the speed of light.

Learners identify combination, decomposition, displacement, and combustion types of redox reactions. They also watch a video clip that demonstrates the reaction of sodium and water.

In this animated activity, learners examine the terms "half-reaction," "oxidizing agent," and "reducing agent" and follow five interactive examples to balance equations for oxidation-reduction reactions. Three problems are provided as a self-check.

Ions are electrically charged particles obtained from an atom or from a chemically bonded group of atoms by adding or removing electrons. Eight examples illustrate the number of protons, neutrons, and electrons in positive ions (cations) and in negative ions (anions).

Learners view an explanation of how to read a graduated cylinder by measuring the lowest portion of the meniscus. A quiz completes the activity.

Learners view several movie clips that demonstrate the use of an indicator to follow the neutralization reaction that occurs when an acid and a base are mixed. Students test their knowledge in a series of questions. Immediate feedback is given.

In this animated object, learners examine the formation of peptide bonds through dehydration synthesis.

Learners examine how the boiling point increases with increasing pressure. An example from industry is given.

In this well-illustrated activity, learners examine the three types of intermolecular forces: dipole-dipole forces, London or Van der Waals forces, and the hydrogen bond. Two interactive questions are included.

In this screencast, we review the positions of metals, metalloids, and nonmetals in the Periodic Table and the general characteristics of each.

Learners examine phase diagrams that show the phases of solid, liquid, and gas as well as the triple point and critical point.

Students read an explanation of chemical formulas in this animated activity. A quiz completes the object.

In this interactive object, learners calculate formula and molecular weights by working through five examples and two problems.

In this animated and interactive object, learners observe how two, three, or four groups of electrons around the central atom cause the shape of the molecule to be linear, trigonal planar, bent, tetrahedral, or pyramidal. Seven examples and eight interactive questions are provided.

In this interactive object, learners identify charges on ions, write new formulas based on charge, and balance equations using coefficients.

Learners examine how melting, vaporization, and sublimation require energy input while freezing and condensation release energy.

Learners examine graphs and read that the heat of fusion is the heat energy absorbed by one mole of solid as it is converted to liquid, while the heat of vaporization is the heat energy absorbed by one mole of liquid as it is converted to gas.